1. Field of the Invention
The present invention relates to an eyeglass frame uniquely designed so that it is not slipped while worn.
2. Description of the Prior Art
According to the standards in the eyeglass art, eyeglasses should be fitted such that the frame contacts the appropriate portions of a wearer's head and is held there, and the frame should be held in such a manner as if it surrounded the wearer's side head without pressing wearer's blood vessels, nerves and the like or pressing the wearer's head locally.
What is important to maintain an inclined portion of the eyeglass frame temple as above will be described below with reference to FIG. 6 (plan view).
The term "behind-the-ear temporal region" or "behind-the ear region" used herein refers hereinafter to the temporal region behind the wearer's ear on the wearer's side head.
The behind-the-ear temporal region plays an important role in wearing eyeglasses. The majority of people have a behind-the-ear temporal region contoured as schematically shown in FIG. 6. To fit the inclined portion of an eyeglass frame temple onto such a contoured region, it is preferable that the inclined portion contact the region on its entire surface. Also, it is preferable that the inclined portion be firmly pressed onto the fore half region a of the concave portion of the behind-the-ear region, while the inclined portion merely touches the rear half region b. Even if the inclined portion is strongly pressed onto the rear half region b, the eyeglass frame temple is not effectively held against the concave portion comprised of the fore and rear half regions a and b and the eyeglasses can not be prevented from being slipped.
However, the curvature of the behind-the-ear region differs from person to person. Accordingly, it is almost impossible in practice, as noted in the art, to adjust the inclined portion so as to contact the fore half region a on its entire surface.
In the prior art, it has not been achieved yet to simply and accurately fit the inclined portion onto the concave portion of the contoured behind-the-ear region.
Heretofore, the inclined portion of an eyeglass frame temple has been fitted by adjusting the bending angle, bending back the inclined portion (i.e., bending the inclined portion outwardly so as to match the end of an end cover with the curvature of the behind-the-ear region) etc. and then actually wearing the eyeglasses to determine whether the inclined portion is well fitted. However, in almost all cases, the adjusted fitness could not be maintained during hours of use. In fact, usually most wearers begin to complain of the fitness of their eyeglasses within a few days of the adjustment, and in many cases, their eyeglasses are readily slipped due to the improper fitness during the wear.
Further, attempts have been made to prevent the slipping of eyeglasses by, for example, (i) enhancing the bending strength of the inclined portion, (ii) shaping or constructing the inclined portion to engage it behind the wearer's auricle, or (iii) attaching a holding member having substantially the same structure as in (ii) to the eyeglass frame temple. However, these structures cannot hold the inclined portion in such a manner as if the eyeglasses surrounded the wearer's side head, and, what is worse, hold the eyeglasses too firmly onto the wearer's face to keep wearing the glasses for a normal period because of wearer's pain and discomfort resulting from the pressure by the holding member, the end cover and the nose pads against the auricles, nose blood vessels and nerves. Furthermore, these eyeglasses are put on and off with far less ease because of their special shapes or structures of the inclined portions or holding members than the eyeglass frames of the normal type.